1. Field of the Invention
This invention relates to a structure to adjust a seat back, and more particularly to one applied to an exercising apparatus, which uses a worm and a worm wheel to adjust a seat back.
2. Description of the Prior Art
A conventional seat of an exercising apparatus is provided with an adjustable seat back. The adjustment is done by operating a pneumatic device underneath the seat pad, and is adjusted by a handle to inflate or to release air. Once the adjustment is done, the pneumatic device is locked to set the seat back at a secured inclining position.
However, the air pumps in a fast speed. Sometimes an operator can hardly control the seat back to the most appropriate position, so they have to do the adjustment continuously or give up after several tries.